1. Technical Field
The present disclosure relates generally to contour measuring probes and, more particularly, to a contour measuring probe with an air guide.
2. Description of Related Art
Manufactured precision objects such as optical components (for example, aspherical lenses) and various industrial components need to be measured to determine whether manufacturing errors of the objects are within acceptable tolerance ranges. Such manufacturing errors are differences between the designed dimensions of the object and the actual dimensions of the object as manufactured. Measured dimensions of the manufactured object are usually regarded as the actual dimensions. A high-precision measuring device, such as a contour measuring probe, is used to measure the objects, with maximum precision being preferred. The contour measuring probe requires applying a predetermined measuring force on measured objects. The contour measuring probe generally includes an air guide having a tube track and a cylindrical sliding tube. The tube track defines a circular through hole for slidably receiving the hollow tube. The sliding tube is capable of floating in the tube track, thus reducing a friction force between the sliding tube and the tube track. However, the cylindrical sliding tube can also rotate in the through hole, such that a measurement precision decreases.
Another contour measuring probe generally includes a base, a linear measuring scale, a displacement sensor, a probe tip, an air guide, and two fixing plates. The linear measuring scale and the air guide are fixed on the base. The air guide includes a tube track and two cylindrical hollow tubes. The tube track defines two circular through holes side by side, in which the hollow tubes are slidably received. A gap between each hollow tube and the tube track can be filled with air, such that the hollow tubes slide in the tube track smoothly. The fixing plates connect the hollow tubes respectively at opposite sides of the tube track. The hollow tubes are parallel to each other. The probe tip is fixed to one fixing plate, and the displacement sensor is fixed to the other fixing plate.
Being fixed together by the fixing plates, the hollow tubes cannot rotate in the tube track. Therefore, the contour measuring probe has higher measurement precision. However, such contour measuring probe must provide two hollow tubes, requiring considerable size and manufacturing cost.
Therefore, there is room for improvement within the art.